This application presents plans for the continuation of correlated research on various aspects of the problems in cancer biology featuring the study of cells infected and transformed by RNA and DNA tumor viruses. Plans in five areas are described. 1. Growth regulation in virus infected cells; 2. Viral and cell membranes; 3. Biology of RNA tumor viruses; 4. Genetic expression in mammalian cells: normal and DNA tumor virus infected cells; 5. Control of gene function at the level of transcription, mRNA processing and translation.